Ugolino, Jean-Baptiste Carpeaux (1862)

Artist: Jean-Baptiste Carpeaux (1827-1875) was an outstanding exponent of 19th-century academic sculpture, bringing to public commissions a lively individuality - sometimes too much individuality for his own good. His masterpiece, La Danse, commissioned for the new Paris Opera, was reviled as an "ignoble saturnalia" when unveiled in 1869.

Carpeaux is no Rodin. His art is by no stretch of the imagination an equivalent to the new painting of Manet and his followers, and yet he was pushing for a realism and vitality in genres that had become cold and formal. In portrait sculptures such as The Imperial Prince and His Dog Nero (1865), Carpeaux is a flowing, lively, three-dimensional Van Dyck.

Subject: In the 32nd canto of his poem Inferno, Dante Alighieri describes how he came across, deep in hell, two heads, all that was visible of two sinners trapped in ice, one chewing on the other's skull "and the other things". In the next canto, the gnawing sinner reveals he is Count Ugolino, and the other Archbishop Ruggieri. In July 1288, the duplicitous Pisan Archbishop Ruggieri imprisoned Ugolino, himself a double-dealing politician, with his two sons and two (or three) grandsons in a tower in Pisa, known afterwards as Hunger; they probably died in March 1289.

In Dante, Ugolino has good reason to chew on the archbishop's head. He and his sons were starved to death. Seeing him gnaw his hands with rage, the sons innocently begged that he eat them. One by one, the boys died. Dante leaves it to the reader's imagination what happened next: "Then hunger proved more powerful than grief."

This punishment - of Ugolino for his cannibalism, of Ruggieri for his cruelty - makes it clear what horrors transpired in the tower. The desire for vengeance is its own hell in the image of Ugolino chewing on his persecutor's skull. Yet Dante himself shares Ugolino's vengefulness, concluding the tale with an invocation to the river Arno to flood shameful Pisa.

Distinguishing features: In 18th- and 19th-century art, Ugolino is a man oppressed by power, like the prisoners in the Bastille; he is noble, tragic, utterly empathetic in his suffering. In Carpeaux's sculpture, he is a Romantic hero. His chin rests in his hand in melancholic thought, like the figure of Lorenzo de'Medici on his tomb by Michelangelo, but he is gnawing on his fingers, surrounded by the dying boys whose suffering drives him to distraction. Carpeaux has illustrated the moment when the boys see Ugolino chew his hands in rage and believe it is from hunger, the moment when they plead that he eat them - the moment when they put this fatal possibility in his mind.

This is also a study in the tense depiction of an intertwined group. Carpeaux began it at the traditional training ground of French artists, the Villa Medici in Rome. As well as the Medici tombs, Ugolino's pose imitates one of the damned in Michelangelo's Last Judgment, not to mention the definitive image of the sublime in classical sculpture, the Laocoon group in the Vatican.

Inspirations and influences: William Blake and Joshua Reynolds made Ugolino an icon of humanity born free but everywhere in chains. Rodin sculpted him in his final madness, groping for his dead sons. The story still has resonance: Seamus Heaney included a translation in his 1979 anthology Field Work, which you can't help reading as about communal hatred, the endless cycle of violence.